Recently, as living environments have significantly improved and living conditions have become better, individuals are increasingly interested in personal health. As a result, a significant amount of research into home medical devices allowing users to easily check their personal physical condition has been conducted and new products have been developed one after another.
In case of a healthy individual, generally, body fluid present within a living body is organically circulated and adjusted to maintain an amount of a body fluid in a predetermined range. Here, body fluid includes constituents such as blood, urine, interstitial fluid, perspiration, and saliva, and in particular, concentrations of constituents of blood, urine (carbohydrates or protein), and the like, in body fluid, are critical indicators indicating a person's physical condition. As for blood, it is important to measure a concentration of constituents such as glucose, hemoglobin, bilirubin, cholesterol, albumin, creatinine, protein, urea, and the like, present in blood.
However, when a living body is afflicted with a disease, a composition or an amount of body fluid constituents may be changed, causing a risky health situation. For example, a concentration of blood glucose is about 80 mg/dl before a meal and about 120 mg/dl after a meal in a healthy individual, and in order to maintain the concentration of blood glucose, the pancreas secretes an appropriate amount of insulin before or after a meal, the secreted insulin being absorbed by the liver and bowels (intestines) and skeletal muscle cells in a living body. Here, if insulin in an amount required for maintaining normal blood glucose is not produced by the pancreas due to a disease or some other reason, an excessive amount of glucose may be present in blood to potentially cause a cardiac disorder or a liver disease, arteriosclerosis, high blood pressure, cataracts, a retinal hemorrhage, neural damage, hearing loss, amblyopia, and the like, and in a worst case scenario, a corresponding patient may die. Thus, it is important to periodically measure a change in constituents of a body fluid of a living body before such an extreme result occurs.
A method for measuring a concentration of blood constituents includes an invasive method of directly collecting a portion of a target material and performing measurement thereon and a non-invasive method of performing measurement without collecting a target material. Due to various problems of the invasive method, technologies to easily diagnose blood liquid constituents in a non-invasive manner have continued to be developed.
For example, in order to measure blood glucose in the existing invasive manner, blood is collected and reacted with a diagnostic reagent, and a clinical analysis device is used or discoloration of a test strip which has reacted with the reagent is quantified. In a case in which blood collection is performed several times every day, a patient may experience a significant amount of pain, may have a high probability of being infected with a disease, and may find it difficult to continuously monitor blood constituents so the patient may have difficulty in properly coping with an emergency as it occurs. In addition, in the case of the strip or the reagent, a large amount of consumables must be used, imposing a financial burden on a user, and such consumables are environmental contamination materials required to be handled in compliance with proper regulations. Also, in the case of a cancer patient, a cancer cell may spread to other organs through blood so whether a cancer cell has spread may be determined through blood constituent test. Here, however, blood should be collected from the cancer patient each time when necessary for a test.
Thus, in order to adjust blood sugar of diabetic patients, determine whether a cancer cell of a cancer patient has spread, or for a physical checkup of a healthy individual, a technology for continuously measuring constituents required for a test in a non-contaminated environment within a living body, without a strip or a consumable or without blood collection, to accurately diagnose a patient condition is required. In order to achieve the object, non-invasive blood measuring devices have been actively researched. For example, Korean Patent Registration No. 10-0731716 discloses contents regarding non-invasive optical measurement of blood constituents (or blood components). However, conventional non-invasive blood measuring devices are inconvenient to use and relatively expensive while a non-invasive blood measuring device that may be easily purchased and used by patients is relatively rare.